docs: def allsec_preorder(h):
      """
      Alternative to using h.allsec(). This returns all sections in order from
      the root. Traverses the topology each neuron in "pre-order"
      """
      #Iterate over all sections, find roots
      roots = root_sections(h)
  
      # Build list of all sections
      sec_list = []
      for r in roots:
          add_pre(h,sec_list,r)
      return sec_list